1. The Field of the Invention
The present invention is directed generally to a lifting device, and more particularly, to a lifting device adapted to remove and install a truck cap or canopy.
2. Background Art
Pickup trucks with open beds have become popular as a means for transporting goods and/or personnel. Various types of removable truck caps have been made available and configured to be used to cover open beds in order to protect the goods placed on the open beds from weather elements and theft. In some instances, truck caps are also used as temporary shelters for camping, outdoor barbecues and the like. While truck caps provide protection for goods when installed on truck beds, it is often desirable to remove it for easy loading and unloading of materials or goods on the truck beds.
A truck cap is typically configured to be easily attachable and detachable to the sidewalls of a truck bed. Reference is made to U.S. Pat. No. 4,927,206 to Murdock for an exemplary truck cap that is easily attachable and detachable to a truck bed. Typical truck caps are relatively bulky and awkward to handle, weighing up to 300 lbs. The size and weight present a significant problem for removal and installation, especially by one person working alone. Typically, a group of at least two people is required to remove a truck cap with each lifting one side of the truck cap and moving it towards the back of the truck and positioning it on a floor or a support. In order to further share the weight load, a group of four people is preferable to lift and remove a truck cap, with each person handling or lifting each corner of the truck cap in concert with others in the group.
U.S. Pat. No. 6,152,427 to Hoslett discloses a truck cap hoisting system comprising a winch, at least one pulley, at least two support channels, at least two lifting strap assemblies, and a lifting line. The truck cap lifting system is preferably installed in a garage. The winch and a guide pulley are attached to a wall of the garage. The lift pulley is attached to a ceiling or an overhead beam. The lifting line is fastened to a lift ring and a reel of the winch. Each lifting strap assembly is threaded through one end of the at least two support channels. The truck cap is hoisted off the pick-up truck by first placing spacers between the truck box and the truck cap and sliding support channels in the gap. The same procedure is repeated for the opposite side. Four S-hooks extending from the at least two lifting assemblies are attached to the lift ring. The winch is then rotated until the truck cap is hoisted to a suitable height. Although this system can be used to perform the same tasks as the present invention, i.e., facilitating the removal and installation of a truck cap, this disclosure reveals a removal system that requires a raised structure that is not supported or otherwise attached to the truck for supporting a detached truck cap. This structure further requires multiple steps in maneuvering of the lifting strap assembly in order to secure S-hooks to the truck cap prior to lifting the cap. In addition, the truck would need to be centrally parked under the lifting strap assembly such that the lifted truck cap could be properly centered.
U.S. Pat. No. 5,993,137A to Harr discloses a hoist for raising and lowering objects that may be attached to a vehicle. The hoist includes a support column and a boom attached thereto. The boom can be raised and lowered by a hydraulic double action cylinder. Both the support column and cylinder are attached to a bracket. The bracket is in turn being rotatably connected to a base unit so that the boom can be rotated as well as raised and lowered. The support column and boom can be adjusted with respect to one another and to the bracket, to balance loads and to adjust the reach of the hoist. The base unit includes outriggers to support and stabilize the hoist, preferably three outriggers in a triangular configuration. Adjustments to the hoists can be made by inserting and removing penetrating pins through adjustment holes in the hoist members. This structure is mountable to a vehicle hitch and includes outriggers and additional hardware to effect rotation of the hoist. The boom is rotatable and the effective length of the boom is adjustable. This disclosure lacks the teachings of a structure or surface for supporting, lifting or positioning a truck cap nor is it easy and quick to set up such a device due to the extraneous outriggers and the rather complex mechanism for rotating the hoist.
U.S. Pat. No. 4,810,158 to Bitzer discloses a kit for enabling one person to remove a truck cap from over a truck bed. The cap is provided with hold down bolt holes. The kit includes detachable forward rollers for attaching to and detaching from a forward portion of the truck cap, and for rollably engaging the truck bed and maintaining the truck cap in rolling engagement with the truck bed when the detachably forward rollers are attached to the truck cap and when the truck cap is disposed over the truck bed. The kit also includes detachable rear wheels for attaching to and detaching from a rear portion of the truck cap and for providing the truck cap with rolling mobility upon removal of the truck cap from the truck bed. This disclosure teaches a maneuver which still requires some amount of manual lifting of the truck cap and is time consuming since a user has to attach and detach a roller or wheel at each corner of the truck cap.
Thus, there exists a need for an apparatus which is easy to install and use that is compact in size, low cost and simple to manufacture.